Magneto-impedance element, and azimuth sensor, autocanceler and magnetic head using the same

Abstract

A magneto-impedance element comprises an alloy composed of at least one of Fe, Co and Ni. The alloy has a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less. The magneto-impedance element shows a change in impedance in response to an external magnetic field by applying an alternating current. The magneto-impedance element is applied to an azimuth sensor, an autocanceler, or a magnetic head.

What is claimed is:  
     
       1. A magneto-impedance element comprising an alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W; and the subscripts a, b, c, x and y satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent ≦x≦18 atomic percent, and 4 atomic percent≦y≦9 atomic percent. 
     
     
       2. A magneto-impedance element according to claim  1 , wherein said alloy further comprises at least one element selected from the group consisting of Ru, Rh, and Ir in an amount of 5 atomic percent or more in total. 
     
     
       3. A magneto-impedance element comprising an alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y and z satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦y≦9 atomic percent, and z≦4 atomic percent. 
     
     
       4. A magneto-impedance element comprising an alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; and the subscripts a, b, c, x, y and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent. 
     
     
       5. A magneto-impedance element according to claim  4 , wherein said alloy further comprises at least one element selected from the group consisting of Ru, Rh, and Ir in an amount of 5 atomic percent or more in total. 
     
     
       6. A magneto-impedance element comprising an alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y, z and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18atomic percent, 4 atomic percent≦y≦9 atomic percent, d≦4.5 atomic percent, and z≦4 atomic percent. 
     
     
       7. A magneto-impedance element according to claim  6 , wherein said alloy further comprises at least one element selected from the group consisting of Ru, Rh, and Ir in an amount of 5 atomic percent or more in total. 
     
     
       8. An azimuth sensor for detecting the direction of the magnetic flux from an external magnetic field and comprising a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; and the subscripts a, b, c, x and y satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, and 4 atomic percent≦y≦9 atomic percent. 
     
     
       9. An azimuth sensor for detecting the direction of the magnetic flux from an external magnetic field and comprising a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y and z satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and z≦4 atomic percent. 
     
     
       10. An azimuth sensor for detecting the direction of the magnetic flux from an external magnetic field and comprising a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; and the subscripts a, b, c, x, y and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent. 
     
     
       11. An azimuth sensor for detecting the direction of the magnetic flux from an external magnetic field and comprising a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; and the subscripts a, b, c, x, y, z and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent, and z≦4 atomic percent. 
     
     
       12. An autocanceler comprising: 
       a magnetic sensor sensing a vector of the magnetic flux from an external magnetic field;  
       a canceling coil for applying a canceling magnetic field having the reverse vector to said magnetic flux detected by the magnetic sensor to a CRT tube; and  
       a control unit for controlling the vector of said canceling magnetic field based on the vector of said magnetic flux of the external magnetic field detected by the magnetic sensor;  
       wherein said magnetic sensor comprises a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current,  
       wherein said soft magnetic alloy has a composition represented by the following formula:  
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; and the subscripts a, b, c, x and y satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent. 
     
     
       13. An autocanceler sensor comprising: 
       a magnetic sensor sensing a vector of the magnetic flux from an external magnetic field;  
       a canceling coil for applying a canceling magnetic field having the reverse vector to said magnetic flux detected by the magnetic sensor to a CRT tube; and  
       a control unit for controlling the vector of said canceling magnetic field based on the vector of said magnetic flux of the external magnetic field detected by the magnetic sensor;  
       wherein said magnetic sensor comprises a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current,  
       wherein said soft magnetic alloy has a composition represented by the following formula:  
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y and z satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4 atomic percent. 
     
     
       14. An autocanceler sensor comprising: 
       a magnetic sensor sensing a vector of the magnetic flux from an external magnetic field;  
       a canceling coil for applying a canceling magnetic field having the reverse vector to said magnetic flux detected by the magnetic sensor to a CRT tube; and  
       a control unit for controlling the vector of said canceling magnetic field based on the vector of said magnetic flux of the external magnetic field detected by the magnetic sensor;  
       wherein said magnetic sensor comprises a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current,  
       wherein said soft magnetic alloy has a composition represented by the following formula:  
        (Fe 1−a−b Co a Ni b ) c B x M y T d    
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; and the subscripts a, b, c, x, y and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent. 
     
     
       15. An autocanceler sensor comprising: 
       a magnetic sensor sensing a vector of the magnetic flux from an external magnetic field;  
       a canceling coil for applying a canceling magnetic field having the reverse vector to said magnetic flux detected by the magnetic sensor to a CRT tube; and  
       a control unit for controlling the vector of said canceling magnetic field based on the vector of said magnetic flux of the external magnetic field detected by the magnetic sensor;  
       wherein said magnetic sensor comprises a magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current,  
       wherein said soft magnetic alloy has a composition represented by the following formula:  
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y, z and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent, and z≦4 atomic percent. 
     
     
       16. A magnetic head comprising a magneto-impedance element, said magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; and the subscripts a, b, c, x and y satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent. 
     
     
       17. A magnetic head comprising a magneto-impedance element, said magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y and z satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and z≦4 atomic percent. 
     
     
       18. A magnetic head comprising a magneto-impedance element, said magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; and the subscripts a, b, c, x, y and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent. 
     
     
       19. A magnetic head comprising a magneto-impedance element, said magneto-impedance element comprising a soft magnetic alloy having a mixed texture of an amorphous phase and a fine crystalline phase having an average crystal grain size of 50 nm or less, said magneto-impedance element showing a change in impedance in response to an external magnetic field by applying an alternating current, wherein said soft magnetic alloy has a composition represented by the following formula: 
       
         
           (Fe 1−a−b Co a Ni b ) c B x M y T d X z    
         
       
       wherein M is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W; T is at least one element selected from the group consisting of Cu, Ag, Au, Pd, and Pt; X is at least one element selected from the group consisting of Si, Al, Ge, and Ga; and the subscripts a, b, c, x, y, z and d satisfy the relationships: 0≦a+b≦0.1, 75 atomic percent≦c≦93 atomic percent, 0.5 atomic percent≦x≦18 atomic percent, 4 atomic percent≦y≦9 atomic percent, and d≦4.5 atomic percent, and z≦4 atomic percent.